JavaScript: Create a specified number of elements and pre-filled string value array

JavaScript Array: Exercise-37 with Solution

Pre-filled String Array

Write a JavaScript function to create a specified number of elements with a pre-filled string value array.

Test Data:
console.log(array_filled(3, 'default value'));
["default value", "default value", "default value"]
console.log(array_filled(4, 'password'));
["password", "password", "password", "password"]

Sample Solution:

JavaScript Code :

// Function to create a new array with 'n' elements, each initialized to the specified 'val'
function array_filled(n, val) {
    // Use Array.apply to create an array-like object with 'n' undefined elements
    // and then use map to fill each element with the specified 'val' converted to a string
    return Array.apply(null, Array(n)).map(String.prototype.valueOf, val);
}

// Output the result of array_filled with 'n=3' and 'val='default value''
console.log(array_filled(3, 'default value'));

// Output the result of array_filled with 'n=4' and 'val='password''
console.log(array_filled(4, 'password'));

Output:

["default value","default value","default value"]
["password","password","password","password"]

Flowchart:

ES6 Version:

// Function to create a new array with 'n' elements, each initialized to the specified 'val'
const array_filled = (n, val) =>
  // Use Array.from to create an array with 'n' undefined elements
  Array.from({ length: n }, () => String(val));

// Output the result of array_filled with 'n=3' and 'val='default value''
console.log(array_filled(3, 'default value'));

// Output the result of array_filled with 'n=4' and 'val='password''
console.log(array_filled(4, 'password'));

Live Demo:

See the Pen JavaScript - Create a specified number of elements and pre-filled string value array-array-ex- 37 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript function that creates an array of a given length filled with a specified string using Array.fill().
• Write a JavaScript function that populates an array with repeated string values using a loop and push().
• Write a JavaScript function that employs Array.from() to generate an array pre-filled with a constant string value.
• Write a JavaScript function that validates input and returns an error if the specified length is not positive.

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